This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Cognitive impairment/dementia affects as many as 80% of Parkinson's patients. The investigators argue that early recognition of cognitive impairment is important in clinical practice for quality of life for both patients and family members. Results of several studies suggest that the Montreal Cognitive Assessment (MCoA) instrument is reliable and valid in detecting cognitive decline the PD population;and may be more sensitive to early and mild cognitive impairment than the Mini Mental State Exam. Key Objectives of the study are to 1) Determine accuracy of the MoCA for detecting mild cognitive impairment in Parkinson's disease;2) Compare accuracy of the MoCA, MMSE and a PD cognition specific assessment test the SCOPA-Cog in ability to detect mild cognitive impairment;and 3) determine the sensitivity of the MoCA to changes in cognition for Parkinson's patients.